[U-Boot] efi_loader query

[Rob Clark]

On Wed, Oct 11, 2017 at 12:13 PM, Suneel Garapati
<suneelglinux at gmail.com> wrote:
> Hi Rob,
>
> I am enlisted on u-boot mailing list and currently trying to use efi
> loader to launch ubuntu distro.
>
> Appreciate your great efforts on this, would definitely help a lot.
>
> I tried to boot grub from u-boot using efi_loader using,
> bootefi <grub-loaded-addr> <fdt addr>

note that the distro-bootcmd stuff should "just work" to avoid needing
to do this step manually

> however I see one error "Error to install/update FDT" while launch
> ubuntu from grub menu.

So, without editing grub.cfg to add 'devicetree' commands, it is
expecting u-boot to load the correct fdt before 'bootefi'.. I have a
patch[1] to do this as part of distro-bootcmd which we are using in
fedora.

[1] https://patchwork.ozlabs.org/patch/821470/

> I could also see
> "Loading Linux.."
> "Loading ramdisk..."
> But jumps back to grub menu instead of booting into linux.
>
> I would like to know if CONFIG_EFI_LOADER will suffice or anything
> else needs to be defined for distro support.

I think also CONFIG_DISTRO_DEFAULTS..  assuming there are no special
hacks in ubuntu's grub build for arm/arm64, at least.  For fedora we
are not using any special arm specific patches for grub (or
shim/fallback) and (at least with the addition of the patch mentioned
above to handled fdt loading in u-boot) it all just works
automatically the same way it does on x86_64 (with all the other
patches that landed for 2017.11 so far).

BR,
-R

> Any suggestions/inputs would be of great help.
>
> Regards,
> Suneel